OBJECTIVE: To investigate the clinical, radiological and electroencephalographic characteristics among patients diagnosed with viral encephalitis and correlate these with functional outcome.
METHODOLOGY: Twenty-eight adult and 32 pediatric viral encephalitis patients in a tertiary hospital were investigated by thorough chart reviews. Outcome was assessed using the Modified Rankin Scale, with score of 0-2 as good outcome and score of 3-6 as poor outcome. Data were analyzed employing chi-square tests (p value 0.05) and multiple logistic regression analysis.
RESULTS: The mean age of patients was 20.2 +/- 16.5 years. There were 31 male and 29 female subjects. History of focal seizures was present in 30 percent of patients, while generalized tonic-clonic type in 63 percent of cases. Twelve percent of the population had status epilepticus. The mean Glasgow Coma Score (GCS) on admission was 11 (range, 4 to 15) Abnormal EEG was present in 84 percent of cases; findings were predominantly generalized slowing of the background activity. CT scan abnormalities were found in 67 percent of patients and these were mainly diffuse cerebral edema and low density lesions, majority involving the frontotemporal region. A total of 39 (67 percent) patients had good outcome and 19 (33 percent) had poor outcome on discharge. Of the 33 patients who had follow up at three months, 31 (94 percent) had good outcome and 2 (6 percent) had poor outcome On univariate analysis, the following factors were correlated with poor outcome on discharge: 1) Age /- 5 years (p On multiple logistic regression analysis, EEG patterns of epileptiform discharges and severe generalized slowing, as well as concomitant infection, were found to have correlation with poor outcome on discharge Of the 32 patients who had serologic tests for HSV, 17 (53 percent) was positive. Modified Rankin Scale scores on discharge and at three months did not differ between HSV-positive and HSV-negative patients (p values, 0.96 and 0.83, respectively). Case fatality rate for herpes encephalitis was 5.88 percent.
CONCLUSION: Age, GCS in the acute phase and the history of status epilepticus could influence the mortality and morbidity of the patients. Moreover, this study has demonstrated the prognostic significance of EEG patterns in viral encephalitis as they correlate with functional outcome on discharge.